20 
MANURES. 
Chalk, or carbonate of lime, . . 0.12 
Magnesia, iron, manganese, clay, 
united 10 the several acids above, 0.14 
100.00 
SECTION IY. 
OF THE ACTION OF MOULD IN CATTLE DUNG-. 
Here, then, we have cattle dung with its several 
ingredients spread out before us. 
We have now to study its action. We need here 
consider only the salts and mould. The water is only 
water, and has no other action than water. The 
mould includes the hay, for that has by chewing, and 
the action of the beast’s stomach, lost so much of its 
character, that, mingled with the slime and bile, &c., 
it more rapidly decays than fresh hay would, placed 
in similar circumstances. During this act of decay, 
as you have already learned, the volatile parts of the 
mould are given off in part. These escape as in 
burning wood, as water or steam, carbonic acid, and 
ammonia. In consequence of this slow mouldering 
fire or decay, the manure heats. Here then we have 
three very decided and important actions produced 
by the vegetable part or mould of cattle dung. First, 
carbonic acid is given off; second, ammonia is form¬ 
ed ; third, heat is produced. Let us now consider 
each of these, and their effects. 
Firstly, the great action of the carbonic acid is 
upon the soil, its earthy parts. It has the same action 
on these, that air, rain, frost, have; it divides and 
reduces them. It not only reduces them to powder, 
but it extracts from the earth potash, and the alkalies. 
This is a very important act, and shows why it is 
necessary that decay, or fermentation, should take 
place in and under the soil among sprouting seeds 
